MRO Magazine

Mill returns to full operation following crusher repairs after fire


May 28, 2012
By PEM Magazine

Osisko Mining Corp. has reported that the Canadian Malartic mill in Quebec returned to full operational status this month (on May 19, 2012). This follows the earlier reported May 9 fire and completion of temporary repairs to the damaged No. 4 cyclone set. Sunday throughput production totaled 41,000 tonnes, and Monday’s throughput was 39,000 tonnes.

The mill resumed partial operation on May 16, with the grinding circuit utilizing three of the four cyclone sets and two of the three ball mills, as well as the semi-autogenous grinding (SAG) unit. Completion of temporary repairs to the fourth cyclone circuit and the completion of scheduled maintenance on the primary and secondary crushers allowed for the resumption of full production on May 19.

Production rates are still at ramp-up levels but have now returned to the pre-fire range. During the past week modifications to the XL2000 cone crusher bowl and liners have been effected under recommendations and supervision from the supplier FLSmidth. Their representatives are currently on site monitoring and adjusting the crusher circuit while trials of the modifications are conducted. Current throughputs during this work are expected to range between 35,000 tpd and 40,000 tpd. Pending successful completion of this work, Osisko expects to see the circuit stabilize in the 40,000 tpd – 45,000 tpd range as the Company awaits the arrival and installation of the second FLSmidth XL2000 cone crusher. The second XL2000 (number 2 of 2 cone crushers comprising the secondary crusher) is currently expected to be installed and operational by July. This should allow the circuit to subsequently increase throughput to 50,000 tpd – 55,000 tpd. Further optimization to the circuit, including the installation in August of the previously announced second pebble crusher, is expected to lead to increased daily throughput by September.

Sean Roosen, president of Osisko, commenting on the return to operations noted: "We are very proud of the speedy effort our team has made in getting the mill up and returned to operation after the fire. We greatly appreciate the outstanding efforts of our employees, contractors and suppliers. The location of the Canadian Malartic Mine has allowed us to respond quickly to the challenges of the past ten days, and really gave us rapid access to the necessary expertise and support infrastructure."


Luc Lessard, senior vice-president of Osisko, noted: "We are continuing to ramp up production, make modifications to improve throughput and stabilize the circuit. During the unplanned stoppage, we accelerated the regular maintenance of key operating units, which should improve our near term performance as we gain better plant availability."

Equipment and building damage from the fire is estimated between $6 million and $8 million. The company is working with its insurance underwriters and adjusters and expects the costs of the physical damages to be fully covered subject to a $250,000 deductible. Permanent repairs of the damage will continue over the next three to four months, with the eventual replacement of the number 4 cyclone set with a new cyclone cluster currently being manufactured by the supplier. Repairs to the damaged overhead crane and the mill roof will also be completed during this period. Minimal impact on production during these final repairs is anticipated.

Osisko Mining operates the Canadian Malartic gold mine in Malartic, Que., and is pursuing exploration on a number of properties, including the Hammond Reef Gold Project in Northern Ontario.